1. Field of the Invention
The present invention relates generally to a disk apparatus, and more particularly to a disk apparatus for writing data to and reading data from a rotating floppy disk by movement of a head carriage.
2. Description of the Related Art
Conventionally, floppy disk apparatuses are widely used in personal computers as external memory devices. In recent years, in an effort to cope with the coming video age, floppy disk apparatuses have begun to be developed that greatly expand memory capacity from the current 1.44 MB to 200 MB or more. In order to expand memory capacity to such a large extent, it is necessary to increase the current 300 rpm rotation speed of the floppy disk by 10 times or more and at the same time increase the current track density of 135 tracks per inch (hereinafter tpi) by 10 times or more, to 2,000 to 3,000 tpi.
In order to reliably write and read data under these high-speed, high-density conditions, the head load pressure of the magnetic head, that is, the pressure exerted by the magnetic head on the floppy disk, becomes an important consideration. Specifically, the ability to precisely adjust the head load pressure of the magnetic head exerted on the floppy disk becomes crucial to reliable writing and reading of data under such conditions.
However, the structure of the conventional floppy disk apparatus is not suitable for making such precise adjustments to the head load pressure. Typically, as shown in FIG. 14, the conventional floppy disk apparatus has a head carriage 11, the head carriage having a lower magnetic head 12 and an upper magnetic head 13. The head carriage further has a supporting frame 14 on the lower portion thereof, the frame being moved in an essentially planar longitudinal direction indicated by the double-headed arrow Y1←xe2x86x92Y2 in FIG. 14 so as to write data to or read data from a rotating floppy disk inserted in the head carriage between the lower magnetic head 12 and upper magnetic head 13. Additionally, the head carriage further has a carriage body 16, a spring plate 17 fixedly mounted on the carriage body 16 and a head arm 18 mounted on the front edge of the spring plate 17. The lower magnetic head 12 is mounted on the front edge of the carriage body 16 and the upper magnetic head 13 is mounted on the front edge of the head arm 18. A head load spring 19 applies head load pressure to the upper magnetic head 13.
However, although it is possible to adjust the head load pressure of the upper magnetic head 13 to an optimum value by changing the stop position of the head load spring 19 at the rear side, that is the Y1 side, it is not possible to adjust the head load pressure of the lower magnetic head 12 because there is no mechanism either for applying head load pressure to the lower magnetic head 12 or for adjusting the head load pressure of the lower magnetic head 12.
As a result, the head load pressure of the lower magnetic head exerted on the rotating floppy disk 15 is not uniformly optimal but differs with each assembled floppy disk apparatus 10, making uniformly reliable data writing and data reading difficult to obtain. Additionally, the lower magnetic head 12 does not track well floppy disks of high density rotating at high speeds.
Accordingly, it is an object of the present invention to provide a floppy disk apparatus in which the problems described above are eliminated.
The above-described object of the present invention is achieved by a floppy disk apparatus comprising:
disk rotating means for supportably rotating a floppy disk;
an upper magnetic head and a lower magnetic head for writing data to and reading data from an upper surface and a lower surface of a floppy disk being rotated by said disk rotating means; and
a head carriage that moves in a direction of a radius of said rotating floppy disk, the head carriage comprising:
a carriage body for supporting said lower magnetic head at a front edge thereof;
a head arm supported by said carriage body for supporting said upper magnetic head at a front edge thereof; and
a head load spring mounted on said head arm for applying head load pressure to said upper magnetic head to press on said upper surface of said floppy disk,
wherein said lower magnetic head comprises means for adjusting a head load pressure of said lower magnetic head exerted on a lower surface of said floppy disk.
By adjusting the head load pressure of the lower magnetic head exerted on the lower surface of the floppy disk, it becomes possible to obtain uniform optimal head load pressure of the lower magnetic head exerted on the floppy disk, thus obtaining reliable data writing and data reading for all floppy disk apparatuses assembled.
Additionally, the above-described object of the present invention is also achieved by said means for adjusting said head load pressure of said lower magnetic head exerted on said lower surface of said floppy disk comprising:
a suspension for generating said load pressure exerted on said lower surface of said floppy disk, a base of said suspension being fixedly mounted on said carriage body and said lower magnetic head being mounted on a front edge of said suspension;
a head load spring portion that elastically deflects to change said head load pressure exerted on said lower magnetic head, said head load spring portion being formed on a part of said suspension; and
an adjustment member movably mounted on said carriage body that operates for changing a state of a deflection of said head load spring portion.
The head load spring portion is formed on a part of the suspension, so changes in the state of the deflection of the head load spring portion result in small changes in the head load pressure of the lower magnetic head. As a result, it becomes possible to precisely adjust the head load pressure of the lower magnetic head so as to reliably write data to and read data from high-density floppy disks rotating at high speeds.
Further, the adjustment member is mounted on the carriage body so as to rotate through a horizontal plane, so the lower magnetic head load pressure adjustment mechanism is not bulky, making it possible to make the floppy disk apparatus slim.
Additionally, the above-described object of the present invention is also achieved by the disk apparatus as described above, wherein the means for adjusting the head load pressure of the lower magnetic head comprises:
a suspension for generating the load pressure exerted on the lower surface of the floppy disk, a base of the suspension being fixedly mounted on the carriage body and the lower magnetic head being mounted on a front edge of the suspension; and
an adjustment member movably mounted on the carriage body so as to be capable of contacting the suspension, the adjustment member operating to adjust the head load pressure generated by the suspension.
Additionally, the above-described object of the present invention is also achieved by the disk apparatus as described above, wherein the adjustment member comprises a contacting portion that contacts the suspension and an operating portion for moving the adjustment member.
Additionally, the above-described object of the present invention is also achieved by the disk apparatus as described above, wherein the operating member of the adjustment member is provided on a surface of a side opposite a surface of a side of the carriage body on which the head arm is provided and a restraining member is provided on the carriage body so as to prevent deformation of the suspension beyond a predetermined point.
Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.